Environment, Fuel-Efficient and Defensive Driving
Domain 8 examines environmentally aware and defensive driving for buses: fuel and energy use, emissions, and the habits that prevent collisions.
Fuel-efficient driving
- Anticipate: release the accelerator early, use engine braking and the retarder, avoid stop-start acceleration.
- Keep engine speed low, shift up early, use cruise control on motorways where appropriate, and switch the engine off during longer waits (idling burns fuel and is restricted by cantonal rules).
- Correct tyre pressure cuts rolling resistance; roof boxes and open windows increase air resistance; unnecessary weight costs fuel.
- Use heating and air conditioning deliberately; check the AdBlue level and allow diesel particulate filter regeneration on longer runs.
- Electric and hybrid buses: use recuperation, plan charging, and drive smoothly to protect range.
Defensive driving
- Observe far ahead, scan mirrors and blind spots, and assume other road users have not seen a large vehicle.
- Keep a safety margin covering your longer braking distance; the two-second rule is a minimum in good conditions, double it when wet and more on ice.
- Protect vulnerable road users: cyclists, pedestrians, children and elderly people. Expect them at stops, crossings and parked cars.
- Adapt to weather and visibility; in fog and heavy rain reduce speed so you can stop within the visible distance.
Worked example
A bus uses 30 L/100 km and covers 80,000 km a year. Smooth anticipation and correct tyre pressure cut consumption by 8 %: 30 × 0.08 = 2.4 L/100 km, which is 2,400 L a year - around CHF 4,000 at CHF 1.70 per litre, plus lower brake wear.
Traps that cost marks
- Warming up the engine stationary for minutes.
- Treating the retarder as free - it still costs fuel and can lock the driven wheels on ice.
- Over-inflating tyres to "save fuel" and losing grip.
- Following so closely that anticipation is impossible.
- Assuming a bus is always seen because it is big.